Disc brakes for bicycles are growing in popularity as consumers demand and bicycle manufacturers strive to provide ever advancing technology on bicycles. Disc brake systems generally consist of a disc which is fixably attached to the hub of a bicycle wheel and a caliper which is fixably attached to a wheel supporting portion of the bicycle frame and which receives the disc between a pair of brake pads which are advanced into and out of contact with the disc along a select axis. The caliper portion of the brake has some structure for attaching a pair of brake pads and securing the pads from movement parallel to the direction of the rotation of the disc as the pads are advanced into and out of contact with the disc. Over time, the brake pads will wear as a result of friction between the pad face and the disc. Therefore, the brake pad assembly must be a user replaceable item. Ideally the brake pad assembly can be replaced by the user quickly, without the use of specialized tools, under field conditions.
To ensure proper disc brake functioning, it is important to maintain a parallel planar alignment between the braking surface of a disc brake pad and the disc. In the event the parallel planar relationship between the pad surfaces and the disc is not maintained, braking efficiency will be decreased and uneven brake pad wear will be experienced resulting in a shortened brake pad useable life.
The caliper holds each brake pad so that the respective faces of each brake pad are planar parallel to each other. Therefore, structures known in the prior art which allow for the adjustment of the position of a disc brake caliper with respect to the disc can be utilized to adjust the orientation of the brake pad faces with respect to the disc. One such device is disclosed in Lumpkin, U.S. Pat. No. 6,230,849 which describes a structure and method of attaching a disc brake caliper assembly to a bicycle frame with the angle of incidence between the axis of pad operation and the plane of the disc being infinitely variable within a defined range. The prior art devices do not provide for the adjustment of the angle of the face of one brake pad independent of the angle of the face of the other. In addition, prior art devices do not allow for the orientation of the pad faces to vary during operation of the brake if the plane of the disc varies during the operation of the brake. For example, certain brakes known in the prior art, such as Buckley et. al. U.S. Pat. No. 5,950,772, provide for the application of braking force by the advancement of one brake pad into contact with a flexible disc. The advancing pad then flexes the disc into contact with a second, stationary, brake pad. This process of flexing an elastic disc into contact with a stationary brake pad involves a slight tilt of the disc from its original plane of orientation. Prior art devices which fix the alignment of the brake pads upon the original alignment of the disc cannot compensate for the misalignment which results from a change in the plane of the disc during normal brake operation.
The present invention is directed toward overcoming one or more of the limitations discussed above.